Resiliently biased rotary speedresponsive switch



June 19, 1956 J. K. GAYLORD ET AL 2,751,453

RESILIENTLY BIASED ROTARY SPEED-RESPONSIVE SWITCH Filed Jan. 29, 1954 IHII l" 19 1f' 51 27 l `9 Zzfor' C/fame di' @any/0rd Paul I." @fazn Unite RESILIENTLY BIASED ROTARY SPEED- RESPNSIVE SWITCH Application January 29, 1954, Serial No. 407,683

3 Claims. (Cl. 2.00-80) This invention relates to improvements in a speedresponsive electric switch and refers particularly to an electric switch which functions to open an electric circuit in response to the rotational speed of a body.

In predetermined types of electrical apparatus it is desirable to deenergize an electrical circuit including said apparatus in response to a predetermined rotary speed of a body which may also be associated with said apparatus. A desirable aspect of a switch which will perform this function is the convenience with which said switch may be adjusted or preset to open at a desired rotational speed.

The present invention is directed to a rotational speed responsive switch which comprises means for so preioading the switching element that it will not open until a desired rotational speed is reached.

The features, objects and advantages of the present invention will be apparent from the accompanying drawing and following detailed description.

In the drawing,

Fig. 1 is a sectional view through a switch embodying the concepts of the present invention.

Fig. 2 is a transverse sectional view of the switch taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmentary detailed perspective view of the switching element employed in the invention.

Fig. 4 is a sectional view similar to Fig. l of a modification of the invention.

Fig. 5 is an enlarged detailed perspective view of the switching element employed in the device shown in Fig. 4.

Although the present invention may be employed in substantially any environment and conjunction with any type of rotating body to control a desired electrical circuit, for purposes of illustration, the device will be described in conjunction with its use on an automotive vehicle wherein the rotating body comprises the usual speedometer cable.

Referring to the drawing and in particular to Figs. 1, 2 and 3, l indicates generally the speed-responsive switch embodying the concepts of the present invention. The device 1 comprises a cup-shaped body 2 having a top closure 3. The cup-shaped body 2 has a bottom 4 and cylindrical side wall S. Within the body 1, a central cylindrical boss 6 is positioned whereby an annular space 7 is provided in the body.

The body also carries a downwardly extending cylindrical sleeve 8 which is provided with an opening 9 for the reception of an end of a speedometer sheath 1d within which a speedometer cable 11 is carried. The cable 11 extends upwardly through the boss 6 and also through a sleeve 12 comprising a portion of closure 3. The sleeve 12 is provided with an opening 13 adapted for the engagement of a spaced end 14 of the speedometer cable sheath.

Within the boss 6, a frictional gripping member 15 engages the speedometer cable 11, said member being embraced by a sleeve 16 which is rotatably positioned within boss 6. A cap 17 is rigidly positioned upon the 2,751,453 Patented June 19, 1956 sleeve 16 and member 15 and is journaled within the closure 3 for rotation with the speedometer cable.

A shaft 18 is secured to cap 17 and extends radially outwardly from said cap into the upper portion of the annular space 7. A vane 19, which may comprise a metal member, is folded upon itself to provide a sleeve 20 at its upper portion, said sleeve being adapted to loosely embrace shaft 13. Shaft 18 is of materially smaller diameter than the inner portion of sleeve 20 and, hence, the sleeve is permitted a degree of radial movement upon said shaft. A lug 21 is carried upon the end of shaft 18 and functions to prevent unintended movement of vane 19 axially of said shaft.

A metal plate 22 is positioned upon the upper face of bottom 4 within space 7, said plate being connected by conductor 23 to an electrical circuit (not shown) to be controlled by the switch. The speedometer cable, member 15, sleeve 16 and vane 19 may be grounded electrically, as indicated at 24 whereby contact of vane 19 and plate 22 completes the electrical circuit.

A pin 25 is mounted upon cap 17 above shaft 18 and the body of vane 19 is provided with an aperture 26. A substantially C-shaped resilient spring 27 carries hook portions 2S at its opposite ends which engage, respectively, the pin 25 and aperture 26. Spring 27 is so flexed normally as to urge vane 19 vertically downwardly so that the lower edge of said vane makes firm frictional contact with the face of plate 22. However, spring 27 resiliently resists rocking movement of the vane 19 about shaft 1S in either direction.

ln operation, a body of electrically non-conductive liquid 29 is adapted to be positioned in the space 7. When the speedometer cable 11 is rotated, the cap 17 rotates and hence shaft 18 carrying vane 19 is rotated within the space 7. As has been hereinbefore described, the normal condition of spring 27 is such that the vane 19 will be disposed vertically downwardly from the shaft 18 and the lower edge thereof will make electrical contact with the plate 22. It can readily be seen that when the vane 19 is rotated by the speedometer cable 11, the liquid 29 will exert a frictional force upon the face of the vane 19 and will tend to rock the vane about shaft 18. This rocking action is opposed by the resiliency of spring 27 and hence, until a predetermined speed of rotation of the vane is reached, the lower edge of the vane will remain in Contact with the plate 22. However, when said predetermined speed is exceeded, the vane 19 will be so canted as to have its lower edge raised in spaced relationship to the plate 22. ln this fashion the electrical circuit comprising the ground 24 and conductor 23 will be broken. in other words, the device so operates that at a predetermined speed of the cable 11 the electric circuit connected to ground 24 and conductor 23 will be broken.

By virtue of the fact that the sleeve 2t) is of materially greater diameter than the shaft 15, the vane 19 can be canted in either direction about said shaft, depending upon the rotation of the cable 11. In other words, by virtue of the fact that the sleeve 20 has a degree of radial movement relative to shaft 18, the vane 19 may pass in either direction about vertical dead center. The arrangement of spring 27 is such that it will offer resilient resistance to canting of the vane 19 in either direction. Hence, the spring 27 comprises a convenient preloading agent which will control the speed at which the vane 19 will be canted. If it is desired to maintain the circuit closed, until a relatively high rotation speed of cable 11 occurs, the spring 27 may be made of relatively heavy construction. lr", on the other hand, it it desired that the circuit be broken at a lower rotational speed of the cable 11, the spring 27 will be of lighter construction.

Referring particularly to Figs. 4 and 5, a modification of the invention is illustrated. The modification relates primarily to the type of vane employed and the manner in which said vane is resiliently biased. Features of the modified device are identical with the device ll and without further description of the parts, corresponding reference numerals will be applied to identical parts.

In the modiiied form of the invention a vane 30 comprising a relatively flat piece of sheet metal is bent upon itself to form sleeves 31. The central portion of the blank comprising the vane 30 is provided with an aperture 32 whereby spaced sleeves are provided. The sleeves 31 embrace shaft 33 carried upon cap 17, the shaft carrying a projection 34 at its outer end to prevent unintended axial movement of the vane upon the shaft. Similar to sleeve 20, the sleeves 31 are of relatively greater diameter than the shaft 33 whereby a degree of radial movement of said sleeves upon said shaft is permitted.

A coil spring 35 is wound upon shaft 33 between the spaced sleeves 3l and an end of said spring is anchored in an aperture 36 provided in shaft 33. The opposite end of the spring is anchored in aperture 37 provided in the downwardly extending portion of the vane 30.

The arrangement is such that spring 35 is in its normal unexed condition when the vane 30 extends vertically downwardly from shaft 33. Hence, rocking of the vane 30 about shaft 33 will be resiliently opposed by the spring 35 whether the vane is rocked in one direction or the other direction from its normal vertical position.

The operation of the modied form of the invention iS similar to the operation of the device l. The vane 30 is rotated by the speedometer cable l1 and during rotation of said vane, it is frictionally restricted by the liquid 29. Under normal conditions, the lower edge of the vane 30 makes electrical contact with the plate 22 and depending upon the strength of spring 35 and the speed of rotation of the cable l1 said contact will be maintained for a predetermined period. When the speed of cable l1 exceeds a predetermined rotational speed, the frictional resistance of the liquid 29 upon the vane 3@ will cause said vane to so rock as to break contact between its lower edge and the plate 22.. Similar to vane 19, the vane 30 may rock in either direction about its normal vertical dead center position and in rocking in either direction it will be resiliently opposed by spring 35.

Although both forms of the present invention have been illustrated and described in conjunction with a rotating speedometer cable, it is to be understood that the operation of the switches may be correlated, and responsive to, the rotation of any rotating body.

We claim as our invention:

l. An electric switch responsive to the rotary speed of a body which comprises a container, an annular electrically conductive plate carried by and within the container, said container being adapted to carry a non-conductive liquid above said conductive member, a rotatable member carried in said container, a vane hingedly connected to said rotatable member with a free end depending portion thereof dipping in said non-conductive liquid and in contact with said plate when said rotatable member is stationary to complete an electrical circuit, means for rotating said rotatable member in a plane substantially parallel to and above said plate to cause the free end depending portion of said vane to be deflected by friction between said non-conductive liquid and said vane to cant said free end depending portion away from and out of contact with said plate to break the electrical circuit, resilient means connected between said vane and said rotatable member for resiliently urging the free edge of the vane into resilient contact with said plate and for resiliently opposing canting of said vane, and means for connecting the vane and plate in an electrical circuit.

2. An electric switch responsive to the rotary speed of a body which comprises a container, an annular electrically conductive plate carried by and within the container, said container being adapted to carry a non-conductive liquid above said conductive member, a rotatable member carried in said container, a vane hingedly connected to said rotatable member with a free end depending portion thereof dipping in said non-conductive liquid and in contact with said plate when said rotatable member is stationary to complete an electrical circuit, means for rotating said rotatable member in a plane substantially parallel to and above said plate to cause the free end depending portion of said vane to be deflected by friction between said non-conductive liquid and said vane to cant said free end depending portion away from and out of contact with said plate to break the electrical circuit, a blade spring connected between said vane and said rotatable member for resiliently urging the free end portion of the vane into resilient contact with said plate and resiliently opposing the canting of said vane, and means for connecting the vane and plate in an electric circuit.

3. An electric switch responsive to the rotary speed of a body which comprises a container, an annular electrically conductive plate carried by and within the container, said container being adapted to carry a non-conductive liquid above said conductive member, a rotatable member carried in said container, a vane hingedly connected to said rotatable member with a free end depending portion thereof dipping in said non-conductive liquid and in contact with said plate when said rotatable member is stationary to complete an electrical circuit, means for rotating said rotatable member in a plane substantially parallel to and above said plate to cause the free end depending portion of said vane to be deflected by friction between said non-conductive liquid and said vane to cant said free end depending portion away from and out of contact with said plate to break the electrical circuit, a coil vspring connected between said vane and said rotatable member for resiliently urging the free end portion of the vane into resilient contact with said plate and resiliently opposing the canting of said vane, and means for connecting the vane and plate in an electric circuit.

References Cited in the tile of this patent UNITED STATES PATENTS 2,319,107 Brandt May 11, 1943 

